title: Impact of an immunoglobulin G-specific enzyme-linked immunosorbent assay on the management of heparin-induced thrombocytopenia.
abstract: OBJECTIVE
  To evaluate whether using an immunoglobulin G (IgG)-specific platelet factor 4 (PF4) test reduces the rate of positive PF4 results and has an impact on prescribing practices of nonheparin anticoagulants (direct thrombin inhibitors and fondaparinux) in patients assessed for heparin-induced thrombocytopenia (HIT).
  
  
  METHODS
  Single-center prospective cohort study with a historical control group.
  
  
  METHODS
  Large academic medical center.
  
  
  METHODS
  A total of 672 patients assessed for HIT.
  
  
  METHODS
  Patients were assessed for HIT by using either an IgG-specific PF4 enzyme-linked immunosorbent assay (ELISA; 336 patients) or a nonspecific PF4 ELISA (336 patients; historical control group).
  
  
  RESULTS
  No significant difference was noted in the proportion of patients with a low, intermediate, or high risk of HIT based on the 4Ts pretest clinical scoring system. The PF4 ELISA was positive in 6.9% versus 11.3% of patients (p=0.04) in the IgG-specific and nonspecific cohorts, respectively. A smaller proportion of patients were prescribed a direct thrombin inhibitor in the IgG-specific cohort (19.4% vs 25.9%; p=0.04). No significant difference in fondaparinux use was noted between the cohorts. The duration of direct thrombin inhibitor therapy, bleeding events, hospital length of stay, and in-hospital mortality was similar in both cohorts.
  
  
  CONCLUSIONS
  Use of an IgG-specific PF4 ELISA was associated with a lower rate of positive PF4 test results. Direct thrombin inhibitor prescribing was also significantly lower during the time period where the IgG-specific PF4 ELISA was used, with no significant differences noted in safety outcomes.
authors.affiliation: Department of Pharmacy, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Katelyn W
authors.initials: KW
authors.lastname: Sylvester
authors.forename: John
authors.initials: J
authors.lastname: Fanikos
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Anger
authors.forename: Lina
authors.initials: L
authors.lastname: Matta
authors.forename: Robert A
authors.initials: RA
authors.lastname: Southard
authors.forename: Nahal
authors.initials: N
authors.lastname: Beik
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Lemire
authors.forename: David M
authors.initials: DM
authors.lastname: Dorfman
authors.forename: Nancy
authors.initials: N
authors.lastname: Berliner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects*; D015331:Cohort Studies; D019468:Disease Management; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010978:Platelet Factor 4 / Q000097:blood; D011446:Prospective Studies; D013921:Thrombocytopenia / Q000097:blood* / Q000139:chemically induced* / Q000628:therapy
chemical_list: D000925:Anticoagulants; D007074:Immunoglobulin G; D010978:Platelet Factor 4; D006493:Heparin
keywords: enzyme-linked immunosorbent assay; heparin-induced thrombocytopenia; immunoglobulin G antibody